A software-defined radio can derail a US train by slamming the brakes on remotely

CISA published CVE-2025-1727 (CVSS 8.1) describing weak authentication in the FRED end-of-train to head-of-train protocol used on freight trains, which allows attackers who can spoof radio traffic (e.g., via low-cost software-defined radios) to send braking commands and potentially cause stoppages or derailments; the protocol is end-of-life and a secure replacement (802.16t) is not expected until ~2027, leaving operators reliant on segmentation and basic mitigations while stakeholders monitor the issue.